SME heavy duty cantilever sump pumps are abrasive resistant pumps for extended wear life and reliability in sumps or pits.
They are designed for applications requiring greater reliability and durability than conventional vertical process pumps can offer.
and corrosive liquids and slurries whilst submerged in sumps or pits.
Sump Pump Construction
Configuration Type
Sump Pump Sump Pump,Metal Vertical Slurry Pump,Mine Dewatering Pumps,SV Sump Pumps Shijiazhuang Minerals Equipment Co., Ltd , https://www.smepump.com
The lightning discharge voltage is high and the time is short. The whole process is accompanied by a variety of physical effects, such as: electrostatic induction, high temperature and high heat, electromagnetic radiation, and light radiation. The joint effects of these physical effects have seriously endangered the safe operation of indoor weak electrical equipment and even endanger the staff. Security. Lightning detection is one of the most basic contents of lightning protection technical service work. Determining whether a building lightning protection device is qualified depends largely on the correctness of the test method used and the reliability of the test data. This requires a detection method. Must be correct, testing data must be reliable. Only in this way can the professionalism and authority of mine detection work be established. The "Technical Specifications for Detection of Lightning Protection Devices for Buildings" implemented on October 1, 2008 comprehensively and systematically specifies the technical requirements and working procedures for detection of lightning protection devices in buildings. The formulation and implementation of standards will better regulate the lightning protection of buildings. Device testing to improve China's lightning disaster prevention capabilities. However, the actual situation is very different and cannot be generalized. The following combination of the author's work experience, on the mine detection technology and methods to communicate and share with everyone.
Second, building lightning detection technology and methods
1. The type of air-termination device for detecting lightning receptors includes needles, belts, nets, wires, and metals. First calculate the protection range of the air-termination device.
(1) Calculate the range of lightning rod and lightning protection line by using the rolling ball method, and pay attention to the influence;
(2) Using the grid method to determine the protection range of the lightning protection zone and the network, to detect the grid size, laying method, connection between the lightning protection zone and downhole, and whether to close the pathway;
(3) Check whether the non-metallic objects on the top of the building and the relevant space outside the nozzles of discharge pipes, breathing valves, exhaust pipes, etc. that emit explosive gas, steam or dust, are also inspected for lightning protection devices. Within the scope of protection. Secondly, the height of the air-termination device, the material specification, the installation position (whether it is easy to be installed at the lightning strike location), the anti-corrosion measures, the connection form and the quality, etc. are tested. In addition, check the roof of the building, the exposed metal objects on the top of the building, whether the down conductors are electrically connected, check whether there are any other electrical circuits on the air terminals, and check the overhead lightning conductors, nets and protected objects. Does the distance meet the requirements, etc.
2, grounding resistance detection (1) voltammetry detection. In the determination of resistance must first estimate the size of the current, select the appropriate section of the insulated wire, in the preliminary test can use the variable resistor r to adjust the current, when the official determination, the variable resistor short circuit, by the ammeter and voltmeter The value can be calculated grounding resistance. Volt-ampere measurement of ground resistance has obvious deficiencies. During the test, the grounding rod is located at a distance of 20 to 50 meters, and the auxiliary grounding distance is 40 to 100 meters from the grounding point. In addition, it is greatly influenced by outside interference and sometimes cannot be measured in a strong voltage region.
(2) Measuring instrument detection method. The single-jaw grounding resistance tester is currently a popular ground resistance tester. Because the instrument is compact and easy to operate, it is the ideal instrument for detecting the grounding device. The instrument is suitable for measuring the grounding resistance of grounding devices such as output pole towers, microwave towers, and lightning rods. Although the single-jaw grounding resistance tester uses a certain frequency signal to eliminate interference during the test, under the condition that there is a large current on the measured cable, the measurement will be interfered, resulting in inaccurate results and unable to be measured. Soil resistivity. The double clamp method also has the same problem. Therefore, it is recommended to use the ground assist method to measure the external interference. For large-scale system grounding, network grounding, soil resistivity testing, and auxiliary devices with good grounding conditions, ground-resistance testers should also be selected for the ground-assist method. The instrument can effectively ensure the repeatability and stability of the earth resistance measurement value.
3. Downhole detection technology First check the number of down conductors and test whether they are connected with a clamp resistance tester. Calculate whether the spacing is qualified, whether the layout is even and whether the corners and corners are set or not, and whether the two main ribs are selected for the downside of the column bars. Note that when a third type of building only uses the steel columns or column steel bars around the building as the deflector, the downline can be set according to the span, and the average distance between the downline can be no more than 25m. For the open-faced downhole, measure its material specification, construction process including connection form and quality, anti-corrosion status, etc.; Also check for other electrical wires that are attached to the lead wires. The test of the down-lead resistance test terminal can test the grounding resistance value according to one down-counter measurement point. For an open-face down-lead (not single) with a disconnect card, disconnect it and test it.
4. Side-thunder and lightning protection measures Testing and testing of high-rise building's first equalizing ring height, distance between rings, material pressure ring specification, laying method, external railings, doors and windows and other large metal objects and lightning protection device connection status, Anti-corrosion measures, connection form and quality, etc. (see tracking and detection of hidden project records). Use a test instrument to measure the ground resistance of a larger metal object or the transition resistance of a lightning protector. The measurement method can be based on two independent measurement points for each measurement point; metal doors and windows, railings and other external metal objects and its reserved ground for every 2 measuring points; glass curtain wall every 10m × 10m counts a measuring point .
5, metal pipe lightning intrusion detection overhead or buried metal pipe lightning protection measures:
(1) The first type of lightning protection building is to detect whether the overhead metal pipeline is connected with a grounding device with lightning protection in and out of the building. Is the pipe within 100m of the building grounded once every 25m or so? The metal pipe in the ground or in the trench shall be connected to the grounding device connected to the lightning protection device at the entrance to the building.
(2) The second type and the third type of lightning protection buildings detect whether the overhead or buried metal pipes are connected to the grounding device of the lightning protection or directly grounded at the entrance or exit of the building. The second type of lightning protection structure also needs to detect if the overhead metal pipeline is grounded at about 25m away from the building. Detect the materials and specifications of the connection and ground connection conductors and further check the connection quality. The grounding resistance of metal pipes, metal gas pipes, and other metal pipes may be measured by entering a measurement point at the entrance of the building for each grounding, and the transition resistance of the equipotential connection may be detected.
Third, the need to pay attention to the issue of lightning protection detection of buildings
1. There should be at least two certified inspectors to participate in the on-site inspection work. One of the inspectors responsible for checking the perception quality, the sampling point of the detection point and the schematic drawing of the measurement point shall be called the sampler; the other shall be responsible for operating the detection instrument for resistance. Testers who test are called testers.
2. Testing should be carried out according to the unit project, record and issue a test report. Testing is a comprehensive inspection of lightning protection devices that should be installed in buildings and facilities. It is not possible to detect only external lightning protection devices or measures, but to ignore the detection of internal lightning protection. It is also not possible to focus on the measurement of measurement items and ignore the inspection of inspection items.
3. The testing organization should correctly quote the corresponding national, industry, and local standards according to the test objects. Validation must be confirmed before the reference to ensure that the cited standard is the latest valid version.
4. The on-site environmental conditions should ensure normal detection. The surface soil resistivity and grounding resistance should be measured on non-rainy days and when the soil is not frozen.
5, detection off-the-shelf should have protective measures to ensure the safety of testing personnel and equipment, climbing dangerous operations should comply with climbing safety regulations; detection instruments, tools, etc. can not be placed in a high place easy to fall, to prevent falling, hurting and damage to instruments and tools.
6. When detecting the lightning protection devices of the power distribution room and the distribution cabinet, they shall be conducted under the guidance of the electrician or relevant management personnel of the inspection unit. Insulating shoes, insulating gloves and insulating mats shall be used to prevent electric shock accidents.
7, in the measurement process due to stray currents, high-frequency interference and other factors, so that the ground resistance table appears when the reading is unstable, you can change the e-pole connection to a shielded wire or choose to change the test frequency, using a frequency selective amplifier or The grounding resistance meter of the narrowband filter is tested to improve its ability to resist interference. Can also be eliminated after the interference factor is eliminated.
8. When detecting lightning protection devices for flammable and explosive dangerous goods (environments), the safety and safety operation rules of the tested unit shall be strictly observed, and shall be conducted under the guidance of the management personnel of the inspection unit, if necessary. The inspected unit may be required to temporarily close the valve of the dangerous goods circulation pipeline.
In short, the building lightning protection site detection technology is the business knowledge that every lightning protection technician must be familiar with. Only with a deep grasp, can we better implement the standardized operation, and make our inspection work more mature.
references:
[1] Building lightning protection design code gb50057-94 (2000 edition) [s]. China Planning Press, 2001.
[2]Building electronic information system lightning protection technical specification gb50343-2004[s]. China Architecture Work Press, 2004.
[3] Specification for construction quality acceptance of building electrical engineering [s]. China Planning Press, 2002.
[4] Technical Specifications for Detection of Lightning Protection Devices in Buildings gb/t31431-2008[s]. China Standard Press, 2008.
[5] Yang Zhongjiang. Lightning detection inspection and acceptance [m]. Beijing: Meteorological Press, 2005.
The heavy duty cantilever design makes the SME Sump Pump ideally suited for heavy continuous handling of abrasive
I. Introduction